Method of making a photographic element for color photography



July 18, 1933.

P. REHLANDER METHOD OF MAKING A PHOTOGRAPHIC ELEMENT FOR COLOR PHOTOGRAPHY Filed April 2, 1932 Patented July 18, 1933 PATENT OFFICE PAUL REHLKNDEB, OF BERLIN-CHARLOTTENIBURG, GERMANY METHOD OF MAKING PHOTOGRAFHIC ELEMENT FOR COLOR PHOTOGRAPHY Application filed April 2', 1932, Serial No. 602,772, and in Germany April 7, 1931.

This invention relates to color photography, more especially to taking, printing and reproducing photographs in natural colors. The object of my invention is to improve the 5 method described in my copending application Ser. No. 496,803 filed November 19, 1030,

and my patent specification No. 1,872,501. In my former applications 1 have de cribed a material for taking the photographs which 0 is provided with a screen of transparent and opaque squares or lines alternating regularly and lying in the same plain which screen is covered with a layer thinner than. 0.1 m.m.

Now I have found that the production of 1 such material may be facilitated by applying a fine-grained photographic emulsion to the transparent support, preferably thinner than 0.1 m.m. and colored with astron g yellow dye stufi whichafterwards can easily be washed out. Then an image of a black-and-white screen is projected through the transparent.

support upon that surface of the said photographic emulsion which is in contact with the rear side of the said transparent support. By

developing this light-impression, fixing,

washing and drying I obtain a black-andwhite screen covered by the base of the photographic emulsion used. Finally a panchromatic photographic emulsion is applied to the free surface of the said base. 1

To obtain images showing natural colors a lens such as described in my copending application Ser. No. 496,804 may be inserted between the taking lens and the light-sensitized material close to the latter.

The screen may consist of alternating dark and transparent lines or figures.

The invention is illustrated in the annexed drawing ofavliich Fig. 1 shows a pelpendicular cross-section through a photographic material composed according to the present invention. Figs. 2 and 3 illustrate two n'iodilications of the screen.

Referring first to Fig. 1, a is the transpaw ent support consisting of celluloid or glass, "for instance. b indicates the screen produced in the surface of the line-grained emulsion c, contacting the layer a. d is the panchromatic emulsion. 0 represents a lens as described in my application Ser. N 0. 496,804.

In Fig. 2 the screen is formed by alternating dark and transparent lines or hands f, f respectively, whereas in Fig. 3 the screen has the configuration of a chess-board.

When employing this material for color photography, the view is taken by means of a suitable tw-oor three-colored diaphragm thru the transparent support and the while and-black screen upon the panchromatie emulsion.

I claim The method of producing a light-sensitized material for taking, copying and reproducing photographs in natural colors, which comprises coating a transparent support with a fine-grained emulsion containing a lightabsorbing dye-stuli soluble in water, photograp-hically copying a screen on that surface of the emulsion which contacts the said support, developing, fixing and wasl'iing, and then coating the other surface of the previous fine-grained emulsion employed with a 35 panchromatic emulsion.

PAUL REHLANDER. 

